A Physical Downlink Control Channel (PDCCH) is defined in a Long Term Evolution (LTE) system. The PDCCH is used to bear DCI. A Control Channel Element (CCE) is taken as a unit by a physical resource transmitted by the PDCCH, a size of one CCE is 9 Resource Element Groups (REGs), namely 36 Resource Elements (REs), and one PDCCH occupies 1, 2, 4, or 8 CCEs. With regard to four kinds of PDCCHs which separately occupies 1, 2, 4, and 8 CCEs, a tree-like aggregation is adopted, namely the PDCCH occupying 1 CCE may begin from any CCE position, the PDCCH occupying 2 CCEs may begin from an even CCE position, the PDCCH occupying 4 CCEs may begin from an integral position multiplied by 4, and the PDCCH occupying 8 CCEs may begin from an integral position multiplied by 8. A Physical Uplink Control Channel (PUCCH) resource corresponding to a Physical Downlink Shared Channel (PDSCH) scheduled by the PDCCH is determined according to the CCE position corresponding to the PDCCH.
Each aggregation level L, L∈{1,2,4,8}, corresponds to one search space, which includes a common search space and a User Equipment (UE)-specific search space.
In the kth sub-frame, a control field bearing the PDCCH is composed of a group of NCCE,k CCEs which are numbered from 0 to NCCE,k−1. The UE shall detect a group of PDCCH candidates on each non-Discontinuous Reception (non-DRX) sub-frame to obtain control information; the detection is referred to decoding the PDCCH in the group in accordance with all DCI formats to be detected. A search space SK(L) on a sub-frame k which has the aggregation level L∈{1,2,4,8} is defined by a group of PDCCH candidates, and the CCE corresponding to a PDCCH candidate m in the search space Sk(L) is defined by the following formula:L·{(Yk+m)mod └NCCE,k/L┘}+i 
wherein i=0, . . . , L−1, Yk is an initiate candidate position of the UE-specific search space, NCCE,k is the number of the CCEs bearing the PDCCH in the kth sub-frame, m=0, . . . , M(L)−1, M(L) is the number of the PDCCH candidates to be detected in the search space Sk(L), and this search space is composed of continuous CCEs;
with regard to the common search space, Yk=0, the value of L is 4 or 8;
with regard to the UE-specific search space, the value of L is 1, 2, 4, or 8, Yk=(A·Yk-1)mod D, wherein Y−1=nRNTI≠0, A=39827, D=65537, k=└ns/2┘, └ ┘ represents rounding down, and ns represents a timeslot number in a radio frame, and nRNTI represents a corresponding Radio Network Temporary Identifier (RNTI).
A LTE-Advanced system aggregates several continuous component carriers dispersed on different frequency bands by adopting a carrier aggregation technique, forming a 100 MHz bandwidth which may be used by LTE-Advanced system, wherein one component carrier may also be taken as a serving cell. In a carrier aggregation scene, a way for cross carrier scheduling may be adopted, multiple component carriers may be scheduled on one carrier, namely the PDCCH of other component carriers may be detected on a certain component carrier. Then a Carrier Indicator Field (CIF) is needed be added in the DCI format, to determine the detected PDCCH is the PDCCH belonging to which component carrier.
When perform the cross carrier scheduling, the UE-specific search space is: L{(Yk+m′)mod └NCCE,k/L┘}+i, wherein m′=m+M(L)·nCI, wherein nCI is a corresponding value in the CIF, and is also called an component carrier index.
In a heterogeneous network, because strong interference exists between different types of base stations, for example, interference of a Macro evolved Node-B (eNodeB) to a Pico eNodeB, and the interference of a Home eNodeB to the Macro eNodeB, a multiple antenna transmission method based on a user-specific pilot frequency in LTE R11 is used to solve the above interference problem; in addition, Frequency domain coordination of inter-cell interference may be implemented by mapping the PDCCH to a PDSCH area, and adopting a frequency division multiplexing way similar to PDSCH multiplexing. This enhanced PDCCH is called enhanced PDCCH (ePDCCH).
Currently, an ePDCCH mapping method mainly includes 2 types, namely a continuous mapping method and a discrete mapping method, a base station configures K resource block pair sets for transmitting the ePDCCH, one resource block pair set includes N resource block pairs, wherein K is 1 or 2, the value of N is 2, 4, or 8; one resource block pair includes 16 enhanced Resource Element Groups (eREGs) numbered from 0 to 15. One resource block pair may be divided into 2 enhanced Control Channel Elements (eCCEs) or 4 eCCEs; when one resource block pair is divided into 2 eCCEs, the eREG corresponding to the eCCE is {0, 2, 4, 6, 8, 10, 12, 14} or {1, 3, 5, 7, 9, 11, 13, 15}; when one resource block pair is divided into 4 eCCEs, the eREG corresponding to the eCCE is {0, 4, 8, 12}, {1, 5, 9, 13}, {2, 6, 10, 14} or {3, 7, 11, 15}. The eCCE corresponding to a continuously mapped ePDCCH (namely an L-eCCE) is composed of the eREG in one resource block pair, the eCCE corresponding to a discretely mapped ePDCCH (namely a D-eCCE) is composed of the eREG of multiple resource block pairs; an antenna port used by one resource block pair includes one or more in {107, 108, 109, 110}. As shown in FIG. 1, FIG. 1 is a structure diagram of the ePDCCH in the related art, wherein R represents a Cell-specific Reference Signal (CRS).
The UE-specific search space of the ePDCCH is composed of discrete eCCE groups, each eCCE group corresponds to continuous eCCEs, but a discrete interval thereof is not determined currently; because a structure of the ePDCCH is different from that of the PDCCH, search space generation ways of the ePDCCH and the PDCCH are also different, therefore the search space generation way when performing cross carrier scheduling is needed to be re-determined, to adapt application of the ePDCCH in a cross carrier scheduling scene. However, the above solution has not been provided in the related art, so that the detection of the ePDCCH is influenced.
In addition, a PUCCH resource corresponding to the PDSCH scheduled by the ePDCCH is determined according to an eCCE position and an Ack/Nack Resource Offset (ARO) corresponding to the ePDCCH, the value of the ARO under Time Division Duplexing (TDD) is still not determined currently.